I bought mine on Ebay, no where states what firmware it is, I'm assuming it's default.
When I boot it there's no blue blink at all, I'm able to connect via serial and send commands. Blue led blinks on Rx, however I do not get any response back to serial monitor (in this case using arduino IDE, but using anything got no response).
First thing I did was connect the usbuart ux=>rx via the ESP: Serial monitor shows that commands are definitely being sent.
Any idea on potential issue?